#include <iostream> 
#include <cstdlib>
using namespace std;

int f(int n)
{
	if(n==1||n==2) return 1;
	else return f(n-1)+f(n-2);
}
int main()
{
	int n;
	while(cin>>n)
	{
		cout<<f(n)<<endl;
	}
}
